21.4.13 TMR3CN0: Timer 3 Control 0
Bit
7
6
5
4
3
2
1
0
Name
TF3H
TF3L
TF3LEN
TF3CEN
T3SPLIT
TR3
T3XCLK
Access
RW
RW
RW
RW
RW
RW
R
RW
Reset
0
0
0
0
0
0
0x0
SFR Page = 0x0; SFR Address: 0x91
Bit
Name
Reset
Access
Description
7
TF3H
0
RW
Timer 3 High Byte Overflow Flag.
Set by hardware when the Timer 3 high byte overflows from 0xFF to 0x00. In 16-bit mode, this will occur when Timer 3
overflows from 0xFFFF to 0x0000. When the Timer 3 interrupt is enabled, setting this bit causes the CPU to vector to the
Timer 3 interrupt service routine. This bit must be cleared by firmware.
6
TF3L
0
RW
Timer 3 Low Byte Overflow Flag.
Set by hardware when the Timer 3 low byte overflows from 0xFF to 0x00. TF3L will be set when the low byte overflows
regardless of the Timer 3 mode. This bit must be cleared by firmware.
5
TF3LEN
0
RW
Timer 3 Low Byte Interrupt Enable.
When set to 1, this bit enables Timer 3 Low Byte interrupts. If Timer 3 interrupts are also enabled, an interrupt will be gen-
erated when the low byte of Timer 3 overflows.
4
TF3CEN
0
RW
Timer 3 Capture Enable.
When set to 1, this bit enables Timer 3 Capture Mode. If TF3CEN is set and Timer 3 interrupts are enabled, an interrupt will
be generated based on the selected input capture source, and the current 16-bit timer value in TMR3H:TMR3L will be cop-
ied to TMR3RLH:TMR3RLL.
3
T3SPLIT
0
RW
Timer 3 Split Mode Enable.
When this bit is set, Timer 3 operates as two 8-bit timers with auto-reload.
Value
Name
Description
0
16_BIT_RELOAD
Timer 3 operates in 16-bit auto-reload mode.
1
8_BIT_RELOAD
Timer 3 operates as two 8-bit auto-reload timers.
2
TR3
0
RW
Timer 3 Run Control.
Timer 3 is enabled by setting this bit to 1. In 8-bit mode, this bit enables/disables TMR3H only; TMR3L is always enabled in
split mode.
1:0
T3XCLK
0x0
RW
Timer 3 External Clock Select.
This bit selects the external clock source for Timer 3. If Timer 3 is in 8-bit mode, this bit selects the external oscillator clock
source for both timer bytes. However, the Timer 3 Clock Select bits (T3MH and T3ML) may still be used to select between
the external clock and the system clock for either timer. Note: External clock sources are synchronized with the system
clock.
Value
Name
Description
0x0
SYSCLK_DIV_12_CAP
_CMP1
External Clock is SYSCLK/12. Capture trigger is Comparator 1.
0x1
EX-
TOSC_DIV_8_CAP_CM
P1
External Clock is External Oscillator/8. Capture trigger is Comparator 1.
0x2
SYSCLK_DIV_12_CAP
_EXTOSC
External Clock is SYSCLK/12. Capture trigger is External Oscillator/8.
0x3
CMP1_CAP_EXTOSC
External Clock is Comparator 1. Capture trigger is External Oscillator/8.
EFM8SB2 Reference Manual
Timers (Timer0, Timer1, Timer2, and Timer3)
silabs.com
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